Freight manipulator with articulated cantilever boom

ABSTRACT

A freight manipulator includes a mobile chassis positioned on a pair of guide tracks and have an articulated cantilever boom extending forwardly thereof. A tool carriage is mounted at the end of the boom and has a pair of freight engaging tools thereon for engaging freight articles. The boom is connected to a two-axis gimbals at the rear of the chassis which allows swinging of the boom about a vertical axis and tilting of the boom about a horizontal tilt axis to increase the positioning range of the freight engaging tools. A boom bearing assembly at the front of the chassis supports the boom on the chassis during movement thereof. A pair of swing cylinders are connected to the chassis and have a chain connecting the ends of their rams to the bearing assembly. The swing cylinders work in opposition to swing the boom. A pair of boom tilt cylinders are connected between the bearing assembly and the boom and operate in unison to tilt the boom.

CROSS-REFERENCE TO RELATED APPLICATION

This is a continuation-in-part of copending application, Ser. No.07/640,995 filed Jan. 14, 1991 and entitled MANIPULATOR FOR MIXEDFREIGHT HANDLING SYSTEM, now U.S. Pat. No. 5,088,873, which is adivision of application, Ser. No. 07/280,720 filed Dec. 6, 1988 andentitled MIXED FREIGHT HANDLING SYSTEM, now U.S. Pat. No. 5,009,560.

FIELD OF THE INVENTION

The present invention relates to article shipping and handling systemsand, more particularly, to a freight manipulator apparatus, for such asystem, which incorporates a laterally swingable and vertically tiltablecantilever boom.

BACKGROUND OF THE INVENTION

There are many systems available and in use for efficiently loading andunloading truck trailers with relatively uniform types of freight. Forexample, if a trailer is loaded with only hand liftable cartons, thetrailer may be unloaded entirely manually, as onto pallets on a dock; ora conveyor may be extended into the trailer and the cartons manuallyplaced onto the conveyor. Similarly, if a trailer is loaded with onlypalleted freight, it may be unloaded fairly efficiently using aconventional fork lift truck.

In some trucking operations, particularly larger general freightcarriers, a great variety of freight may be shipped from a number ofdiverse origins to a central facility for local or distanttransshipment. At the central facility, freight from the arriving trucksis unloaded, sorted according to destination, then reassembled intoloads in such a manner as to most economically utilize the trucks.Because of the nature of this kind of shipping operation, trucks oftenarrive at a central facility with mixed freight loads, hand liftablearticles interspersed with palleted freight and other types of bulky orheavy articles which are not suitable for manual unloading. Such mixedfreight loads are often referred to as "LTL" freight for "Less (than)Truck Load".

In the past, the utilization of labor and equipment in loading andunloading such LTL trailers has often been inefficient and uneconomical.Because of the indeterminate mix of manually liftable freight andfreight requiring mechanized handling and possible uncertainty ofarrival times of trucks, it is often difficult to provide an optimumcombination of labor and equipment for unloading such trucks to assurethat the laborers are not overworked at certain times and left idle atothers. On some docks, only certain designated persons ma be permittedto operate fork lift trucks. Also, a single fork lift truck or conveyormay be required to service multiple dock positions. As different typesof freight are encountered in loading or unloading the trailer, workersare often left standing about idly as equipment is awaited andchangeover thereof occurs. If conveyors are employed in the trailers formanually liftable articles, time and effort are consumed in extendingand retracting the conveyors when a fork lift is required to handleheavier freight.

In loading truck trailers with mixed types of freight for offloading atseveral locations, it is desirable to position the freight in such amanner as to minimize handling at each stop. Thus, a load for a firststop is positioned rearmost in the trailer, and a load for a last stopis positioned toward the front of the trailer. Problems similar to thoseencountered in unloading mixed freight occur in loading mixed freightonto trailers.

The results of such inefficiency, among other disadvantages, are thatdock workers and unloading equipment are inefficiently employed, and thedocks and truck trailers are tied up awaiting loading or unloading.Shipping costs are thereby increased and profits to the warehousingfacility and/or trucking company are diminished.

SUMMARY OF THE INVENTION

The present invention provides a freight manipulator system including aswingable and tiltable cantilever boom for use in cooperation with atelescoping conveyor positioned below the manipulator in a mixed freighthandling system. The mixed freight handling system combines amanipulator and a conveyor for each trailer dock position to facilitateloading and unloading mixed freight loads including mixes of handliftable articles and heavier freight such as palleted items. Themanipulator system generally includes a manipulator chassis mounted onparallel guide tracks in straddling relation to the conveyor and acantilever boom connected by a two axis gimbals to the chassis to enableswinging of the boom laterally and tilting of the boom vertically.Freight engaging tools, such as fork tines, are mounted on a front endof the boom by an articulated tool carriage which allows raising andlowering the tools, pivoting about a vertical axis, tilting the toolsvertically, and lateral shifting of the tools.

The structure of the manipulator chassis includes a boom support bodymounted on four legs forming a tunnel through which the telescopingconveyor extends and retracts and through which articles on the conveyorpass. Flanged wheels are mounted on the legs and engage the guide tracksto guide movement of the manipulator. The rails have rack gears mountedtherebelow, and the rear legs have rotary motors with spur gears whichmesh with the rack gears to propel the manipulator.

The boom extends from the gimbals, located at a rear end of the top ofthe chassis, past a boom bearing structure at the front of the top ofthe chassis and is cantilever supported therefrom. The boom bearingstructure includes a plurality of rollers mounted on the boom whichengage a top surface of the chassis to provide for movable engagement ofthe boom during lateral swinging of the boom. Lateral swinging of theboom allows the fork tines to engage or offload freight articles at thelateral extremities of the truck trailer, such as near the trailer wallsor the edges of a flat bed trailer. A pair of swing cylinders arepivotally connected to the chassis and have their rams connected by achain which is also connected to the boom in the vicinity of the boombearing structure. The swing cylinders are operated in opposition tolaterally swing the boom. The boom bearing structure is provided with apair of tilt cylinders positioned on opposite sides of the boom andconnected between the bearing structure and the boom. The tilt cylindersare operated in unison to lift and lower the boom.

The tool carriage is connected to the boom by an extendible mast whichincludes an upper frame pivotally connected to the end of the boom forpivoting about a vertical axis. A pair of mast pivot cylinders areconnected to the boom and have the ends of their rams connected by achain. The chain is meshed with a sprocket connected to the upper frame.The pivot cylinders work in opposition to pivot the mast relative to theboom. The mast is formed by three telescoped mast frames. A middle framehas rollers engaging guide rails on the upper frame, and, similarly, alower frame has rollers engaging guide rails on the middle frame. A toolframe has the fork tines mounted thereon and has rollers engaging guiderails on the lower frame.

A pair of secondary main lift cylinders of the mast are engaged betweenthe upper frame and the middle frame. The middle frame has a pair ofsprocketed pulleys mounted thereon, and a pair of lift chains engage thepulleys and have their ends connected between the upper frame and thelower frame. By this arrangement, as the cylinders extend to lower themiddle frame, the chain and pulley arrangement causes correspondinglowering of the lower frame. A particular advantage of the configurationof the mast is that the overall lifting or lowering range of thepreferred mast approaches double the stroke length of the mast liftcylinders.

A primary lift cylinder having a pair of sprocketed pulleys thereon hasits ram connected to the top of the lower frame. A pair of tool carriagelift chains are connected between the lower frame and the tool frame andengage the pulleys. Extension of the tool carriage lift cylinder lowersthe tool carriage while retraction of the cylinder lifts the toolcarriage. The chain and pulley arrangement gives the tool carriage alift range approximately twice the stroke length of the primarycylinder.

The fork tines are L-shaped and have their top ends pivotally andslidably received on a transverse tine support bar. A pair of tool tiltcylinders are connected to the tool frame on opposite sides thereof andhave their rams connected by a tool tilt bumper extending across thetool frame. Extension and retraction of the tilt cylinders in unisontilts the fork tines relative to the tool frame. The fork tines areindividually shiftable laterally. Each tine has a ram of a tool shiftcylinder engaged therewith, the cylinder being connected to the toolframe. The tool shift cylinders may be operated individually, in unison,or in opposition to selectively position the tines laterally of the toolframe.

In a preferred embodiment of the manipulator, a fixed length boom isemployed whereby the freight engaging tools are extended into thetrailer entirely by movement of the manipulator chassis toward thetrailer. In a modified embodiment of the manipulator, a telescoping boomis provided in which telescoping boom sections are extended andretracted by hydraulic cylinders. On a manipulator with an extendibleboom, the tools may be extended into the trailer by a combination of themovement of the chassis and the extension of the boom. Retraction of theboom sections results in a compact structure for the modifiedmanipulator.

OBJECTS AND ADVANTAGES OF THE INVENTION

The principal objects of the present invention are: to provide improvedequipment for handling freight in a mixed freight handling system; toprovide such equipment which is adapted for use with an extendible ortelescoping conveyor which is translatable into a trailer for conveyingmanually liftable articles; to provide an independently translatablefreight manipulator for use with such a conveyor which includes achassis configured to straddle the conveyor, the manipulator being usedfor handling freight not suitable for manual handling, such as palletedloads and the like; to provide such a manipulator in which the boom isconnected to the chassis by a gimbals allowing lateral swinging andvertical tilting of the boom to thereby enable engagement and depositingfreight articles at a variety of vertical and lateral positions within atruck trailer; to provide such a manipulator in which the chassis issupported on manipulator tracks parallel to and outside of conveyorguide tracks and has a tunnel therethrough for passage of articles onthe conveyor through the chassis and for independent translation of themanipulator relative to the conveyor; to provide such a manipulatorincluding a tool carriage connected to the chassis by a cantilever boomwhich allows a freight engaging tool to be extended to the front end ofa standard size trailer; to provide a modified embodiment of themanipulator employing a telescoping or extendible boom having the toolcarriage mounted on an end thereof; to provide such a manipulatorwherein a variety of freight engaging tools, such as fork tines andextensions, a drum clamp, a rug pole, a jib boom, or the like, areinterchangeably connectible to the tool carriage for handling a varietyof types of freight; to provide such a manipulator wherein the toolcarriage is capable of a wide range of articulation, such as lifting ofthe fork tines, independent lateral shifting of fork tines, pivoting thetool carriage through at least 180 degrees about a vertical axis,tilting of the fork tines, and the like; to provide such a manipulatorwith such a tool carriage with a multiple stage negative liftarrangement, that is, an arrangement which is extended to lower the forktines and retracted to lift the tines; to provide such a tool carriagewhich is connected to the boom by an extendible mast including an upperframe pivotally connected to the end of the boom for pivoting about avertical axis, a middle frame slidably mounted on the upper frame, and alower frame slidably mounted on the middle frame and having the toolcarriage slidably mounted on the lower frame and on which the fork tinesare mounted; to provide such a tool carriage mast in which a pair ofsecondary lift cylinders are connected between the upper frame and themiddle frame, a pair of sprocketed pulleys are mounted on the middleframe, and a pair of chains are connected between the upper frame andthe lower frame and engage the pulleys whereby, as the secondarycylinders are extended or retracted to respectively lower or raise themiddle frame relative to the upper frame, the lower frame isrespectively lowered or raised relative to the middle frame; to providesuch a tool carriage mast wherein a primary lift cylinder has isconnected to the top of the lower frame and has a pair of sprocketedpulleys mounted on a cylindrical shell connected to the ram thereof anda pair of primary lift chains are connected between the lower frame andthe tool carriage frame and engage the pulleys whereby extension andretraction of the primary cylinder respectively lowers and raises thetool carriage; to provide such a tool carriage including a pair of toolshift cylinders connected to the tool carriage frame and engaging thefork tines respectively and operable independently or in cooperation toselectively position the tines laterally of the tool frame; to providesuch a manipulator which may be controlled to perform certain automaticfunctions such as the translation of the chassis to the extremities ofthe manipulator tracks, translation of the chassis to a position to setoff or pickup a unit of freight, interchanging of freight engagingtools, parking of the manipulator, and the like; to provide such amanipulator wherein the extendible conveyor, in an extended and loweredcondition, may remain in the trailer without interference as the toolcarriage of the manipulator is extended into the trailer to engage aunit of nonmanually liftable freight; to provide such a manipulatorwhich can be operated by a single worker to load or unload a trailer;and to provide such a freight manipulator system with an articulatedcantilever boom which is economical to manufacture, efficient andconvenient in operation, and which is particularly well adapted for itsintended purpose.

Other objects and advantages of this invention will become apparent fromthe following description taken in conjunction with the accompanyingdrawings wherein are set forth, by way of illustration and example,certain embodiments of this invention.

The drawings constitute a part of this specification and includeexemplary embodiments of the present invention and illustrate variousobjects and features thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a fragmentary side elevational view of a mixed freighthandling system including a freight manipulator with an articulatedcantilever boom which embodies the present invention, with a verticallytilted position of the boom and a raised front end of a telescopingconveyor shown in phantom lines.

FIG. 2 is a view similar to FIG. 1 and shows the manipulator in anextended condition with freight manipulating tools positioned in atrailer and engaging a unit of freight, a lowered position of the toolsand an extended condition of the telescoping conveyor being shown inphantom lines.

FIG. 3 is a top plan view of the mixed freight handling system with alaterally swung position of the boom and a laterally swing head end ofthe conveyor shown in phantom lines.

FIG. 4 is an enlarged fragmentary side elevational view of themanipulator with portions broken away to illustrate details of a gimbalsconnecting the boom to the manipulator chassis and with a tiltedposition of the boom illustrated in phantom lines.

FIG. 5 is an enlarged fragmentary top plan view of the manipulator andillustrates details of hydraulic swing cylinders employed to swing theboom laterally.

FIG. 6 is a view similar to FIG. 5 with portions broken away toillustrate further details of the swing motor arrangement and with swungpositions of the boom shown in phantom lines.

FIG. 7 is a further enlarged fragmentary transverse sectional view takenon line 7--7 of FIG. 6 and illustrates details of sprockets and chainsof the swing motor arrangement and a boom bearing assembly.

FIG. 8 is a transverse sectional view taken on line 8--8 of FIG. 4 andillustrates guide and support structure for the manipulator, thetelescoping conveyor, and the fixed conveyor and cooperatingrelationships thereamong.

FIG. 9 is a greatly fragmentary enlarged side elevational view taken online 9--9 of FIG. 8 and illustrates details of a drive mechanism for themanipulator chassis.

FIG. 10 is a greatly enlarged fragmentary transverse sectional viewtaken on line 10--10 of FIG. 9 and illustrates further details of themanipulator chassis drive mechanism and counterbalance rollers of thechassis.

FIG. 11 is a greatly enlarged fragmentary transverse sectional viewtaken on line 11--11 of FIG. 4 and illustrates details of a front wheelof the manipulator chassis.

FIG. 12 is an enlarged fragmentary side elevational view of the frontend of the manipulator boom and illustrates details of the connection ofa freight manipulator tool carriage to the boom.

FIG. 13 is an enlarged fragmentary top plan view of the front end of themanipulator boom and illustrates details of the guide arrangements amongthe component frames of an extendible mast of the tool carriage withportions of the boom broken away to illustrate a pivot motor assemblyfor the tool carriage mast.

FIG. 14 is a view similar to FIG. 12 and illustrates the tool carriagemast in an extended and lowered condition and further illustratesdetails of the frame lift motor arrangements of the tool carriage mast.

FIG. 15 is an enlarged front elevational view of the manipulator andillustrates further details of the tool carriage and mast with a loweredposition of the tool carriage shown in phantom lines.

FIG. 16 is a view similar to FIG. 13 at a somewhat reduced scale andillustrates the tool carriage in a pivoted position about a verticalaxis relative to the boom, with alternate positions of fork tinesthereof shown in phantom lines.

FIG. 17 is an enlarged transverse sectional view taken on line 17--17 ofFIG. 13 and illustrates details of the tool carriage mast as viewed fromthe rear thereof.

FIG. 18 is a greatly enlarged fragmentary longitudinal sectional viewtaken on line 18--18 of FIG. 16 and illustrates details of fork tineshifting cylinders and fork tine tilting cylinders of the tool carriage,with a tilted position of a tine shown in phantom lines.

FIG. 19 is a fragmentary side elevational view of the system of thepresent invention incorporating a modified embodiment of the manipulatorwhich employs an extendible boom formed of telescoping sections.

FIG. 20 is a view similar to FIG. 19 and illustrates the extendible boomwith the telescoping sections retracted.

DETAILED DESCRIPTION OF THE INVENTION

As required, detailed embodiments of the present invention are disclosedherein; however, it is to be understood that the disclosed embodimentsare merely exemplary of the invention, which may be embodied in variousforms. Therefore, specific structural and functional details disclosedherein are not to be interpreted as limiting, but merely as a basis forthe claims and as a representative basis for teaching one skilled in theart to variously employ the present invention in virtually anyappropriately detailed structure.

Referring to the drawings in more detail:

The reference numeral 1 generally designates a mixed freight handlingsystem including a freight manipulator 2 which embodies the presentinvention. The system 1 also includes a telescoping conveyor 3 whichcooperates with the manipulator 2 to load or unload mixed types offreight carried by a truck trailer 4. The freight manipulator 2 includesan articulated cantilever supported boom 5 with a tool carriage 6mounted at an end thereof for loading or unloading freight articles 7which are not capable of being handled manually. The telescopingconveyor 3 is provided to facilitate the loading or unloading ofarticles 8 which can be handled manually.

Referring to FIGS. 1-3, and 8, the extendible or telescoping conveyor 3includes a rear base section 14, a middle lift section 15, and a fronthead section 16. The lift section 15 is pivotally connected to the basesection 14, and the head section 16 is pivotally connected to the liftsection 15, both for pivoting about respective axes transverse to alongitudinal extend to the conveyor 3. The head section 16 includes arear pitch frame 18 which is pivotally connected to a front end 19 ofthe lift section 15 to allow a pitching or inclined relationship betweenthe head and lift sections 15 and 16 and a front swing frame 20pivotally connected to the pitch frame 18 for pivoting about a verticalaxis, that is, for swing movements by the head section 16.

A set of conveyor lift struts 23 are connected to the lift section 15and the head section 16 and are operable to raise the head section 16 tofacilitate the manual transfer of articles 8 from the illustratedconveyor 3 to the trailer 4 or vice versa. The struts 23 are connectedto the front end 19 of the lift section 15, and surface engaging wheels25 are journaled at outer ends of the struts 23. A pair of hydrauliclift cylinders (not shown) are pivotally connected between the struts 23and the pitch frame 18 of the head section 16. The struts 23 are pivoteddownwardly as the lift section 15 is inclined, and links (not shown),which are connected between the struts 23 and the pitch frame 18, pivotthe head section 16 downwardly in such a manner that it remainssubstantially horizontal when lifted.

The telescoping conveyor 3 cooperates with a fixed conveyor 27 which isillustrated to be positioned in overlapping relation to the telescopingconveyor 3. This arrangement allows the telescoping conveyor 3 toreceive articles 8 from the fixed conveyor 27 for loading in the trailer4. The system 1 may also be configured for unloading articles 8 from thetrailer 4 with the telescoping conveyor 3 positioned overlapping thefixed conveyor 27 whereby the fixed conveyor 27 receives articles 8 fromthe telescoping conveyor 3. Further details of conveyors similar to thefixed conveyor 27 and the telescoping conveyor 3 are available in U.S.Pat. No. 5,009,560 referred to above.

The freight manipulator 2 generally includes a mobile chassis 30, thecantilever boom or boom assembly 5 mounted on the chassis 30, the toolsupport carriage 6 mounted at a front end 33 of the boom 5, and toolengaging tines or forks 35 mounted on the tool carriage 6. The boom 5 ispivotally connected to the chassis 30 by a gimbal or universal coupling37 to allow pivoting about a vertical axis, or swinging, and pivotingabout a horizontal axis, or tilting. The boom assembly 5 has a length toallow the forks 35 to reach freight 7 at a front end of a trailer 4 ofcertain standard lengths when the chassis 30 is positioned at itsforwardmost position near an edge 44 of a dock 45.

Referring to FIGS. 1-3, 8 and 10, a guide means or guide and supportassembly 48 for the fixed conveyor 27, the telescoping conveyor 3, andthe freight manipulator 2 of the system 1 is illustrated. An elongatedguide trench 49 is formed into a surface 50 of the dock 45 to receivethe guide assembly 48. A plurality of cross beams or ties 53 arepositioned across the trench 49 on support pads 54 at spaced locationsalong the trench 49. Each cross tie 53 has a pair of legs 55 upstandingtherefrom to support a respective elongated guide rail assembly 57. Eachof the illustrated guide rail assemblies 57 includes a lower plate 58, atubular beam 59, and an upper plate 60 spaced upwardly from the lowerplate 58 at approximately the same level as the surface 50 of the dock45. The tubular beam 59 may, alternatively, be formed by a pair ofinwardly facing and welded channel members. A lower surface 61 (FIG. 10)of the lower plate 58 has an elongated rack gear 62 mounted thereonwhich cooperates with the manipulator 2 for propulsion thereof, as willbe detailed further below.

Portions of the fixed conveyor 27 are mounted on the upper plates 60 ofthe guide rail assemblies 57, or extensions thereof, in spaced relationabove the telescoping conveyor 3. The telescoping conveyor 3 issupported on the upper plates 60 by way of rimmed wheels 64 positionedon opposite sides of the conveyor 3 and engaging inner edges of theupper plates 60. At least one of the wheels 64 has a conveyor motor (notshown) engaged therewith and operable to propel the conveyor 3 between aretracted condition spaced away from the trailer 4 and a fully extendedcondition in which the head section 16 and the lift section 15 of theconveyor 3 enter or invade the trailer 4. The guide assemblies 57 extendfrom a location at which the manipulator tines 35 are fully retractedfrom the trailer 4 to guide ends 66 (FIG. 2) spaced from the edge 44 ofthe dock 45 at which the manipulator tines 35 are able to reach a frontend (not shown) of the trailer 4, of an appropriate size for the lengthof the boom 5, in a fully extended condition of the manipulator 2.

Referring to FIGS. 4-8, the manipulator chassis 30 is formed by aframework including a pair of longitudinal side beams 71 connected by afront cross beam 72 and a rear cross beam 73 (FIG. 6), a pair of frontlegs 74 depending from the front cross beam 72, and a pair of rear legsdepending from the rear cross beam 73. The cross beams 72 and 73 and thelegs 74 and 75 are positioned and spaced apart in such a manner as todefine an article receiving clearance or tunnel 76 (FIG. 8) through thechassis 30 through which articles 8 on the fixed conveyor 27 and thetelescoping conveyor 3 may pass without interference by portions of thechassis 30.

Referring to FIGS. 4 and 9-11, each of the legs 74 and 75 has a wheelframe 77 mounted at an end thereof with a respective rimmed wheel 78journaled therein. The wheels 78 engage the upper and outer surfaces ofthe upper plates 60 of the guide assemblies 57. Each of the wheel framesof the rear legs 75 has a drive mechanism 80 mounted thereon forself-propulsion of the manipulator 2. Each of the illustrated driveassemblies 80 includes a drive mechanism support plate 82 depending fromthe associated wheel frame 77 of a rear leg 75. A rotary manipulatordrive motor 83 is mounted on the plate 82 and has a drive gear 84 (FIG.10) mounted on a shaft 85 thereof. The illustrated drive motors 83 arerotary hydraulic motors; however, other types of motors could beemployed, such as electric motors. The drive gears 84 are meshed withthe rack gears 62 mounted on the lower surfaces 61 of the lower plates58 of the rail assemblies 57.

The chassis 30 includes at least one position sensor or resolver 86associated with one of the drive assemblies 80, such as on the rightside as illustrated, to determine the position of the manipulator 2along the guide assembly 48. The sensor 86 includes a position sensorgear 87 (FIG. 9) which meshes with the rack gear 62. The use of thedrive gears 84 and the sensor gear 87 in cooperation with the rack gear62 provides for positive propulsion of the manipulator 2 and positivesensing of the position of the manipulator 2 for communication to acontrol system (not shown) of the mixed freight handling system 1. Theposition sensor 86 may be any type of appropriate mechanism operating byany conventional means for converting rotary motion into datarepresenting linear position along the track assemblies 57, such asmagnetic or photoelectric "click" counters, binary encoders, or thelike.

The length and weight of the boom 5, the tool carriage 6, and anyfreight 7 carried by the tool carriage 6 create moments which tend totip the manipulator 2 in the direction of the tool carriage 6. Tocounter such tipping tendencies, the chassis 30 is provided withcounterbalance rollers 88 (FIG. 10) journaled on the support plates 82on each rear leg 75 and engaging the lower surfaces of the upper plates62 of the rail assemblies 57.

Referring particularly to FIGS. 4 and 6, the gimbals 37 is mounted in agimbals frame 90 formed by the rear cross beam 73, a pair of oppositeside members 91, and a top cross member 92. A swing pin 93 (FIG. 6) isaffixed between the top member 92 and the rear cross beam 37 and has aswing 19 sleeve 94 rotatably received thereon. A tilt pin 95 is attachedto the swing sleeve 94, as by welding, and has a rear end 96 of the boom5 pivotally mounted thereon. The gimbals 37 provides the boom 5 withpivoting capability in two axes: swinging about a vertical axis formedby the swing pin 93 and tilting about a horizontal axis formed by thetilt pin 95.

The manipulator boom 5 is supported on the chassis 30 by the gimbals 37and the gimbals frame 90 and by a boom bearing assembly 100, which alsoforms a boom lift assembly on the illustrated manipulator 2. Referringto FIGS. 4-8, the boom bearing assembly 100 includes a bearing frame 101formed by a lower plate 102 positioned on a roller block 103 having, asillustrated, four boom bearing rollers 104 journaled thereon. Therollers 104 engage an upper surface of the front cross beam 72 of thechassis 30. A pair of laterally spaced boom swing abutments 105 arepositioned in upstanding relation from the lower plate 102 adjacentopposite side walls or sides 106 of the boom 5 and are engaged by thesides 106 of the boom 5 during swinging movements thereof to transfermotion to the bearing frame 101. A lower wall 107 of the boom 5 engagesand rests on the lower plate 102 of the boom bearing frame 101.

FIGS. 4-7 illustrate a swing motor mechanism 110 for swinging the boom 5to the left and right about the swing pin 93. In the illustratedmanipulator 2, a pair of swing cylinders 111 are connected to the outerends of the rear cross beams 73. Rams 112 of the swing cylinders 111 areinterconnected by a swing sprocket chain 113 which is connected to theboom 5 in the vicinity of the boom bearing assembly 100 by a swinganchor 114 (FIG. 7). The swing chain 113 passes about a pair of swingsprockets 115 which are rotatably mounted in swing sprocket brackets 116affixed between the front cross beam 72 and the chassis side beams 71 oneach side of the chassis 30. Front ends of the cylinders 111 rest onswing cylinder support blocks 117 mounted on the chassis side beams 71.

The swing cylinders 111, which are preferably hydraulic, are operated inopposition, one extending while the other retracts, to pivot the boom 5about the vertical swing pin 93 to thereby swing the tool carriage 6 tothe right or left of a centerline position of the boom 5. The swingingcapability of the boom 5 of the manipulator 2 of the present inventionallows the freight engaging tools or tines 35 to be moved through thelateral extremities of the trailer 4 to engage freight articles 7 at anylateral position between side walls 118 (FIG. 2) of the trailer 4 with arelatively narrow width of the tool carriage 6. As the boom 5 is swung,the sides 106 of the boom 5 engage the abutments 105 such that the boombearing assembly 100 is moved with the boom 5 to support the boom on thechassis 30 during such movements. On the illustrated manipulator 2, theboom 5 has a swinging range of approximately nine degrees to the leftand to the right of a centerline position of the boom 5.

Referring to FIGS. 4-8, a boom tilt motor mechanism 120 is connected toand cooperates with the boom bearing frame 101. A pair of boom tiltbrackets 121 are affixed in upstanding relation to an upper wall 122 ofthe boom 5 or, alternatively, to the side walls 106 of the boom 5. Aboom tilt cross beam 123 is connected to the brackets 121 and extendsoutwardly of the brackets 121. A pair of boom tilt cylinders 124 areconnected to the lower plate 102 of the boom bearing frame 101 and havetheir rams 125 connected to the ends of the cross beam 123. Thecylinders 124 are operated in unison to tilt the boom 5 about thehorizontal tilt pin 95. On the illustrated manipulator 2, the tilt rangeof the boom 5 is from substantially horizontal to about two degreesabove horizontal. The tilting capability of the boom 5 is not strictlynecessary for effective employment of the manipulator 2 to handle thefreight articles 7. However, the ability to tilt the boom 5 provides anextra degree of vertical range for the tool carriage 6 and the tools 35of the manipulator 2.

The illustrated manipulator boom 5 includes a rear section 130 and afront section 131 (FIGS. 1-3). The rear section 130 is of a constantrectangular cross section. The front section 131 diminishes inrectangular cross section from the rear section 130 to a front end 33 ofthe boom 5 to reduce the weight of the front end 33. The illustratedboom 5 is of a built-up box beam configuration formed by a lower channelincluding a web forming the lower wall 107 and side flanges forming theside walls 106 with a top plate welded on the top edges of the sidewalls 106 and forming the top wall 122. Internal reinforcing members(not shown) strengthen the boom structure to extend a substantiallength, in a cantilever manner, forward of the boom bearing assembly100. Alternatively, other types of cantilever beam configurations may beemployed on the manipulator 2 of the system 1. In particular, while theboom 5 is described and illustrated as a fixed length boom, it couldalso be configured as an extendible boom, as will be described furtherbelow.

Preferably, the boom 5 is of a length to enable the fork tines 35 toreach freight articles 7 positioned at a front end (not shown) of thetrailer 4 of a standard length. The manipulator 2 of the presentinvention, with a fixed length boom 5, is intended principally forloading and unloading freight articles 7 from relatively shorter typesof trailers 4, such as "city" trailers having lengths of about 32 feetand "pup" trailers having lengths of about 27 to 28 feet. Longer "linehaul" trailers, having lengths of 45 to 48 feet, are best accommodatedby telescoping, non-cantilever booms, such as disclosed in U.S. Pat. No.5,009,560.

FIGS. 12-18 illustrate a multiple stage freight lift apparatus or mast140 of the manipulator 2 of the system 1 and its cooperation with theboom 5. The mast 140 comprises three telescoped lift frames including anupper frame 141, a middle frame 142, and a lower frame 143. The upperframe 141 includes a pair of spaced apart vertical side rails 145connected by an upper cross plate 146, a middle cross plate 147, and alower cross member 148 (FIG. 17). The middle frame 142 includes a pairof side rails 150 connected by an upper cross member 151 and a lowercross member 152. Similarly, the lower frame 143 includes a pair of siderails 154 connected by an upper cross member 155 and a lower crossmember 156.

Referring to FIGS. 12, 13, and 16, the mast 140 is pivotable about avertical axis by operation of a mast pivot mechanism 157. The upper andlower cross plates 146 and 147 of the upper frame 141 have a verticalmast pivot shaft 158 connected therebetween. The shaft 158 is pivotallymounted in the front end 33 of the boom 5. A mast sprocket 159 isaffixed to the shaft 158 and has a sprocket chain 160 meshed therewith.A pair of mast pivot cylinders 161 are connected to the side walls 106of the front end 33 of the boom 5 and have rams of the cylinders 161interconnected by the chain 160. The cylinders 161 are operated inopposition, in a manner similar to the swing cylinders 111, to pivot themast 140 about a vertical axis formed by the shaft 158. As isillustrated in FIG. 16, the pivot mechanism 157 provides the mast 140and the tool carriage with at least a 90 degree pivot range to each sideof the boom 5, enabling the manipulator to deposit or engage freightarticles 7 along the sides of the guide assembly 48 of the system 1.

The side rails 145, 150, and 154 form guide tracks on their respectiveframes 141, 142, and 143 of the mast 140. Referring to FIG. 13, theillustrated side rails 145 of the upper frame 141 are inwardly turnedchannels, while the side rails 150 and 154 of the middle and lowerframes 142 and 143 respectively have I-shaped cross sections. The siderails 150 of the middle frame 142 have rollers 165 mounted thereon atupper and lower locations and engage the side rails 145 of the upperframe 141. Similarly, the side rails 154 of the lower frame 143 haverollers 166 which engage the side rails 150 of the middle frame 142. Thefork tines 35 are mounted on the tool carriage 6 having rollers 168which engage the side rails 154 of the lower frame 143.

The mast 140 includes a primary lift mechanism 170 to lift the toolcarriage 6 relative to the mast 140 and a secondary lift mechanism 171to extend and retract the mast frames 142 and 143 relative to the upperframe 141 to respectively lower and raise the tool carriage 6 andthereby extend its lift range. The secondary lift mechanism 171 includesa pair of hydraulic secondary lift cylinders 173 connected to the uppercross plate 146 of the upper frame 141 and having rams 174 connected tothe lower cross member 152 of the middle frame 142. A pair of laterallyspaced sprocket pulleys 175 are mounted on the middle frame 142 near theupper cross member 151 thereof and have a pair of secondary liftsprocket chains 176 meshed respectively therewith. Each of the chains176 is connected between the lower cross member of the upper frame 141and the lower cross member 156 of the lower frame 143. Upon extension ofthe cylinders 173, the middle frame 142 is lowered relative to the upperframe 141 thereby lowering the pulleys 175. As the pulleys 175 arelowered, the lower frame 143 is lowered correspondingly by way of thechains 176. Retraction of the cylinders 173 reverses the process toraise the lower frame 143 and middle frame 142 relative to the upperframe 141. The secondary lift mechanism 171 has an extension capabilitycomparable to approximately double the stroke length of the cylinders173.

Referring to FIGS. 14 and 17, the illustrated primary lift mechanism 170includes a single hydraulic primary lift cylinder 180 which is connectedto the upper cross member 155 of the lower frame 143. A ram 181 of thecylinder 180 has a cylindrical shell 182 connected to a lower endthereof. The shell 182 provides a mounting for a pair of primary liftsprocket pulleys 183 which are trunnion mounted on opposite sides of atop end of the shell 182. Primary lift sprocket chains 184 are meshedrespectively with the sprockets 183, and each has one end connected tothe lower cross member 156 of the lower frame 143 and the opposite endconnected to an anchor 185 on the tool carriage 6. When the cylinder 180is retracted, the tool carriage 6 is raised to the top of the lowerframe 143. Conversely, extension of the cylinder 180 lowers the toolcarriage 6 to the bottom of the lower frame 143. Thus, the tool carriage6 has a lift range approximately twice the length of the stroke of thecylinder 180.

Referring to FIGS. 15, 17, and 18, the tool carriage 6 includes a toolcarriage frame 190 having the rollers 168 mounted on brackets 191extending rearwardly therefrom. A tool support bar 192 extends acrossthe frame 190 and has upper mounting sleeves 193 (FIG. 18) of the forktines 35 rotatably and slidably received thereon. Each of the tools ortines 35 is substantially L-shaped and includes an upper leg 194connected to a lower foot 195 at a heel region 196 of the tine 35. Themounting sleeves 193 are positioned at top ends of the legs 194. A pairof fork tilt cylinders 197 are pivotally mounted on the frame 190 andhave rams 198 thereof connected by a fork tilt bumper 199 extendingacross the frame 190 at a lower end. The bumper 199 engages the tines 35at the heel regions 196 such that extension of the cylinders 197 causesouter ends 200 (FIG. 14) of the tines 35 to be tilted upwardly. Thetines 35 are generally tilted upwardly after engaging a freight article7 to positively retain a freight article 7 thereon and prevent thearticle 7 from slipping off the tines 35. The tines 35 are tilted backto a horizontal orientation when the freight article 7 is deposited tofacilitate withdrawal of the tines therefrom.

The tines 35 are independently shiftable laterally to maximize theflexibility of the manipulator in engaging freight articles 7. A pair oftine shift cylinders 205 are connected to opposite side walls 206 of theframe 109 and are oriented in opposite lateral directions. Each cylinder205 has a ram 207 including a tab 208 at its outer end which is orientedto engage a pair of tool shift abutments 209 formed on the sleeve 193 ofan associated tine 35. Extension of the cylinders 205 positions thetines 35 at their maximum spread, while retraction of the cylinders 205draws the tines 35 closest to a centerline of the tool carriage frame190.

Preferably, the manipulator propulsion motors 83, the boom swingcylinder 111, the boom tilt cylinders 124, the mast pivot cylinders 161,the secondary mast lift cylinders 173, the primary mast lift cylinder180, the fork tilt cylinders 197, and the fork shift cylinders 205 ofthe manipulator 2 are all hydraulic. Hydraulic fluid may be supplied toand returned from the various hydraulic motors of the mobile manipulator2 in any conventional manner. As is diagrammatically illustrated in FIG.8, a flexible conduit 211 carries hoses (not shown) which supplyhydraulic fluid to the various motors of the manipulator 2 and alsoelectrical cables (not shown) by which the manipulator 2 is controlled.Alternatively, a hydraulic pump and reservoir (not shown) may be mountedon the chassis 30 to supply the motors of the manipulator 2 whereby theconduit 211 only carries power cables (not shown) and control cables.

A conduit channel 212 extends along the guide assembly 48 and issupported by pads 213 positioned on a floor of the guide trench 49 andbrackets 214 which are connected to the cross ties 53. The conduit 211is mechanically connected to one of the drive mechanism support plates82. The conduit 211 lies in the channel 212 and flexes upwardly t followforward movements of the manipulator 2 toward the dock edge 44. Reversemovements of the manipulator 2 return the conduit 211 to the channel212.

FIGS. 19 and 20 illustrate a modified embodiment 220 of the manipulatorof the freight handling system 1 of the present invention which isprovided with a telescoping extendible boom assembly 221 which iscantilever mounted on a chassis 222 of the modified manipulator 220. Thechassis 222 is substantially similar to the chassis 30 of themanipulator 2 and has a two axis gimbals 223 connecting the boomassembly 221 thereto and a boom bearing assembly 224 movably supportingthe boom assembly 221 thereon. The chassis 222 includes a pair of boomswing cylinders 225 to laterally swing the boom assembly 221 and a pairof boom tilt cylinders 226 to tilt the boom assembly 221.

The illustrated boom assembly 221 includes an outer rear section 230having an inner front section 231 telescoped thereinto. The frontsection 231 is supported by an external bearing structure 232 mounted onthe front end of the rear section 230 and has a similar type of bearing(not shown) mounted on an upper side thereof which engages the inside ofan upper wall of the rear section 230. The illustrated boom assembly 221has a pair of boom extension cylinders 233 connected between the rearsection 230 and the front section 231 external to the sections 230 and231. Alternatively, a single cylinder (not shown) could be connectedbetween the boom sections 230 and 231 within the boom assembly 221.

The manipulator 220 has freight engaging tools 235 mounted on a toolcarriage 236 connected by an extendible mast 237 to the front end 238 ofthe front section 231. The mast 237 may be substantially similar to themast 140 of the manipulator 2. The extendible boom assembly 220 allowsthe tools 235 to be extended into a trailer 240 to engage freightarticles 241 by a combination of the movement of the chassis 222 andextension of the boom assembly 221. Additionally, the extendible boom221 when retracted results in a more compact manipulator 220 than themanipulator 2 with the fixed length boom 5, although the extendible boom221 is somewhat more complex and requires more complex handling ofhydraulic hoses (not shown) to service the mast 237 and tool carriage236.

It is to be understood that while certain forms of the present inventionhave been illustrated and described herein, it is not to be limited tothe specific forms or arrangement of parts described and shown.

What is claimed and desired to be secured by Letters Patent is asfollows:
 1. A freight manipulator system for transferring discretefreight articles between spaced apart first and second locations, saidsecond location being within an elongated article transporting vehicleand said first location being external to said vehicle, said systemcomprising:(a) elongated rail means extending from said first locationtoward said second location and terminating at a rail end between saidlocations; (b) a manipulator chassis supported and guided on said railmeans and movable therealong; (c) an elongated cantilever boom pivotallyconnected to said chassis to enable swinging said boom about asubstantially vertical swing axis, said boom extending toward saidsecond location; (d) swing motor means engaged between said boom andsaid chassis and operable t pivot said boom about said swing axis; (e)tool means mounted on an end of said boom and operable to releasablyengage a discrete freight article to lift and transfer same; (f) chassismotor means drivingly engaged between said chassis and said rail meansand operable to propel said chassis on said rail means between aretracted condition at said first location and an extended condition atsaid rail end, said tool means invading said second location with saidchassis in said extended condition; and (g) said chassis has a front endand a rear end; (h) a swing pivot joint is positioned in spaced relationto said front end and pivotally connects said boom to said chassis; and(i) boom bearing means, including a load bearing member, is engagedbetween said boom and said chassis and movable with respect to saidchassis, and located in spaced relation along said boom from said swingpivot joint.
 2. A system as set forth in claim 1 wherein said swingmotor means includes:(a) a linear swing motor connected between saidboom and said chassis and operative to swing said boom about said swingaxis upon extension and retraction of said swing motor.
 3. A system asset forth in claim 1 wherein:(a) said boom is further pivotallyconnected to said chassis to enable tilting said boom about a horizontaltilt axis; an (b) tilt motor means is engaged between said chassis andsaid boom and is operable to tilt said boom about said tilt axis.
 4. Asystem as set forth in claim 3 and including:(a) a universal couplingpivotally connecting said boom to said chassis to enable swinging saidboom about said swing axis and tilting said boom about said tilt axis.5. A system as set forth in claim 3 wherein:(a) said chassis has a frontend and a rear end; (b) a tilt pivot joint is positioned in spacedrelation to said front end and pivotally connects said boom to saidchassis; and (c) said tilt motor means includes a linear tilt motorconnected between said boom and said bearing means and operable to tiltsaid boom about said tilt axis upon extension and retraction of saidtilt motor.
 6. A system as set forth in claim 1 wherein:(a) a pluralityof wheels are journaled on said chassis in spaced apart relation; and(b) said rail means includes a pair of laterally spaced guide railsrollingly engaged by said wheels.
 7. A system as set forth in claim 6wherein:(a) said wheels include a pair of spaced apart rear wheelspositioned on opposite sides of a rear end of said chassis opposite saidboom; (b) each of said rails includes an upper surface engaged by saidwheels on an associated side of said chassis and a lower surface facingaway from said upper surface; and (c) each of said rear wheels hasassociated therewith at least one counterbalance roller journaled onsaid chassis and engaging the lower surface of an associated rail tocounter tipping moments resulting from the weight of said boom
 8. Asystem as set forth in claim 1 wherein said chassis motor meansincludes:(a) said rail means including a guide rail with a toothed rackgear formed thereon; (b) a chassis motor mounted on said chassis andincluding a rotary chassis motor shaft; and (c) a spur gear positionedon said shaft and meshed with said rack gear such that rotation of saidshaft propels said chassis along said rail.
 9. A system as set forth inclaim 1 and including:(a) tool articulation means connecting said toolmeans to said end of said boom and enabling selective articulation ofsaid tool means to engage and release an article.
 10. A system as setforth in claim 1 wherein:(a) said chassis includes means forming aclearance space below said chassis to enable movement of said chassisover articles and the movement of articles beneath said chassis.
 11. Asystem as set forth in claim 1 wherein:(a) said boom is an extendibleboom capable of being extended and retracted relative to said chassis.12. A freight manipulator system for transferring discrete freightarticles between spaced apart first and second locations, said secondlocation being within an elongated article transporting vehicle and saidfirst location being external to said vehicle, said systemcomprising:(a) elongated rail means extending from said first locationtoward said second location and terminating at a rail end between saidlocations; (b) a manipulator chassis supported and guided on said railmeans and movable therealong; (c) an elongated cantilever boom pivotallyconnected to said chassis and extending toward said second location; (d)a universal coupling pivotally connecting said boom to said chassis toenable swinging said boom about a substantially vertical swing axis andtilting said boom about a horizontal tilt axis; (e) swing motor meansengaged between said boom and said chassis and operable to pivot saidboom about said swing axis; (f) tilt motor means operatively engagedbetween said boom and said chassis and operable to pivot said boom aboutsaid tilt axis; (g) tool means mounted on an end of said boom andoperable to releasably engage a discrete freight article to lift andtransfer same; (h) chassis motor means drivingly engaged between saidchassis and said rail means and operable to propel said chassis on saidrail means between a retracted condition at said first location and anextended condition at said rail end, said tool means invading saidsecond location with said chassis in said extended condition; and (i)said chassis includes a chassis body supported on a plurality of spacedapart chassis legs to form an article clearance space below said chassisbody to enable movement of said chassis over articles and the movementof articles beneath said chassis.
 13. A system as set forth in claim 12wherein:(a) said chassis has a front end and a rear end; and (b) boombearing means is engaged between said boom and said chassis in spacedrelation along said boom from said gimbals means.
 14. A system as setforth in claim 13 wherein said tilt motor means includes:(a) a lineartilt motor connected between said boom and said bearing means andoperable to tilt said boom about said tilt axis upon extension andretraction of said tilt motor.
 15. A system as set forth in claim 13wherein said tilt motor means includes:(a) a pair of linear tilt motorspositioned on opposite sides of said boom, connected between said boomand said bearing means, and operable to tilt said boom about said tiltaxis upon extension and retraction of said tilt motors.
 16. A system asset forth in claim 13 wherein said swing motor means includes:(a) alinear swing motor connected between said boom and said chassis andoperable to swing said boom about said swing axis upon extension andretraction of said swing motor.
 17. A system as set forth in claim 13wherein said swing motor means includes:(a) a pair of linear swingmotors connected to said chassis; (b) sprocket means mounted on saidchassis on opposite sides of said boom; and (c) chain means connected tosaid boom and to each of said pair of swing motors such that said boomis swung about said swing axis upon coordinated extension and retractionof said pair of swing motors.
 18. A system as set forth in claim 12 andincluding:(a) tool articulation means connecting said tool means to saidend of said boom and enabling selective articulation of said tool meansto engage and release an article.
 19. A system as set forth in claim 12and including:(a) tool articulation means connecting said tool means tosaid end of said boom and enabling selective articulation of said toolmeans through multiple degrees of freedom to engage and release anarticle.
 20. A system as set forth in claim 12 wherein said boomincludes:(a) a plurality of boom sections positioned in slidingtelescoped relation; and (b) extension motor means connecting said boomsections and operable to extend and retract said sections to therebyextend and retract said boom relative to said chassis.
 21. A freightmanipulator system for transferring discrete freight articles betweenspaced apart first and second locations, said second location beingwithin an elongated article transporting vehicle and said first locationbeing external to said vehicle, said system comprising:(a) elongatedrail means extending from said first location toward said secondlocation and terminating at a rail end between said location; (b) amanipulator chassis supported and guided on said rail means and movabletherealong; (c) an elongated cantilever boom pivotally connected to saidchassis to enable swinging said boom about a substantially verticalswing axis, said boom extending toward said second location; (d) swingmotor means engaged between said boom and said chassis and operable topivot said boom about said swing axis; (e) tool means mounted on an endof said boom and operable to releasably engage a discrete freightarticle to lift and transfer same; (f) chassis motor means drivinglyengaged between said chassis and said rail means and operable to propelsaid chassis on said rail means between a retracted condition at saidfirst location and an extended condition at said rail end, said toolmeans invading said second location with said chassis in said extendedposition; (g) said rail means including a guide rail with a toothed rackgear formed thereon; and (h) said chassis motor means includes a chassismotor mounted on said chassis, a rotary chassis motor shaft, and a spurgear positioned on said shaft and meshed with said rack gear such thatrotation of said shaft propels said chassis along said rail.